<template>
  <div>
    
<ul>
  <li v-for="(item,index) in arr" :key="index">{{item}}</li>
</ul>
<button @click="addFn">点击增加</button>
  </div>
</template>

<script>
export default {
  name: 'VueThreeApp',

  data() {
    return {
      arr:['老大','老二','老三']
    };
  },

  mounted() {
    
  },

  methods: {
    addFn(){
      this.arr.splice(1,0,'新来的')
    }
  },
};
</script>

<style>

</style>